{  Statement: http://acmp.ru/?main=task&id_task=580
   Verdict: Accepted
}
uses
    SysUtils, Math;

const
    EPS:double = 1e-6;

var
    a,b,c,r:longint;
    p:double;
    
begin
reset(input,'input.txt');
rewrite(output,'output.txt');
read(a, b, c, r);
p := (a + b + c) / 2;
if sqrt((p - a) * (p - b) * (p - c) / p) - r >= -EPS then write('YES') else write('NO'); 
end.
